xref: /netbsd-src/lib/libcurses/PSD.doc/twinkle1.c (revision b4beac8f5fe8499fcd44ff0de7ab2f4ae0861845)
1 .\" Copyright (c) 1980, 1993
2 .\"	 The Regents of the University of California.  All rights reserved.
3 .\"
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
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7 .\" 1. Redistributions of source code must retain the above copyright
8 .\"    notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\"    notice, this list of conditions and the following disclaimer in the
11 .\"    documentation and/or other materials provided with the distribution.
12 .\" 3. All advertising materials mentioning features or use of this software
13 .\"    must display the following acknowledgement:
14 .\"	This product includes software developed by the University of
15 .\"	California, Berkeley and its contributors.
16 .\" 4. Neither the name of the University nor the names of its contributors
17 .\"    may be used to endorse or promote products derived from this software
18 .\"    without specific prior written permission.
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20 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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22 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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31 .\"
32 .\"	@(#)twinkle1.c	8.1 (Berkeley) 6/8/93
33 .\"
34 # include	<curses.h>
35 # include	<signal.h>
36 
37 /*
38  * the idea for this program was a product of the imagination of
39  * Kurt Schoens.  Not responsible for minds lost or stolen.
40  */
41 
42 # define	NCOLS	80
43 # define	NLINES	24
44 # define	MAXPATTERNS	4
45 
46 typedef struct {
47 	int	y, x;
48 } LOCS;
49 
50 LOCS	Layout[NCOLS * NLINES];	/* current board layout */
51 
52 int	Pattern,		/* current pattern number */
53 	Numstars;		/* number of stars in pattern */
54 
55 char	*getenv();
56 
57 int	die();
58 
59 main()
60 {
61 	srand(getpid());		/* initialize random sequence */
62 
63 	initscr();
64 	signal(SIGINT, die);
65 	noecho();
66 	nonl();
67 	leaveok(stdscr, TRUE);
68 	scrollok(stdscr, FALSE);
69 
70 	for (;;) {
71 		makeboard();		/* make the board setup */
72 		puton('*');		/* put on '*'s */
73 		puton(' ');		/* cover up with ' 's */
74 	}
75 }
76 
77 /*
78  * On program exit, move the cursor to the lower left corner by
79  * direct addressing, since current location is not guaranteed.
80  * We lie and say we used to be at the upper right corner to guarantee
81  * absolute addressing.
82  */
83 die()
84 {
85 	signal(SIGINT, SIG_IGN);
86 	mvcur(0, COLS - 1, LINES - 1, 0);
87 	endwin();
88 	exit(0);
89 }
90 
91 
92 /*
93  * Make the current board setup.  It picks a random pattern and
94  * calls ison() to determine if the character is on that pattern
95  * or not.
96  */
97 makeboard()
98 {
99 	reg int		y, x;
100 	reg LOCS	*lp;
101 
102 	Pattern = rand() % MAXPATTERNS;
103 	lp = Layout;
104 	for (y = 0; y < NLINES; y++)
105 		for (x = 0; x < NCOLS; x++)
106 			if (ison(y, x)) {
107 				lp->y = y;
108 				lp->x = x;
109 				lp++;
110 			}
111 	Numstars = lp - Layout;
112 }
113 
114 /*
115  * Return TRUE if (y, x) is on the current pattern.
116  */
117 ison(y, x)
118 reg int	y, x; {
119 
120 	switch (Pattern) {
121 	  case 0:	/* alternating lines */
122 		return !(y & 01);
123 	  case 1:	/* box */
124 		if (x >= LINES && y >= NCOLS)
125 			return FALSE;
126 		if (y < 3 || y >= NLINES - 3)
127 			return TRUE;
128 		return (x < 3 || x >= NCOLS - 3);
129 	  case 2:	/* holy pattern! */
130 		return ((x + y) & 01);
131 	  case 3:	/* bar across center */
132 		return (y >= 9 && y <= 15);
133 	}
134 	/* NOTREACHED */
135 }
136 
137 puton(ch)
138 reg char	ch;
139 {
140 	reg LOCS	*lp;
141 	reg int		r;
142 	reg LOCS	*end;
143 	LOCS		temp;
144 
145 	end = &Layout[Numstars];
146 	for (lp = Layout; lp < end; lp++) {
147 		r = rand() % Numstars;
148 		temp = *lp;
149 		*lp = Layout[r];
150 		Layout[r] = temp;
151 	}
152 
153 	for (lp = Layout; lp < end; lp++) {
154 		mvaddch(lp->y, lp->x, ch);
155 		refresh();
156 	}
157 }
158